OK, smart move from Lansweeper
I guess you could change them in the DB, in tblassets field assettype.
The 'supported' way though is to modify the asset state (to eg. 'decommissioned'), export all needed data for these assets , and delete those older then x (eg. 90) days.
Just like you would do in your Active Directory, when someone leaves the company, you mark him as disabled (for in case he'd change his mind
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) and delete the user after 3 months.